Hydraulic shock absorber



Oct. 6, 1936.

w. w. RIEDEL 2,056,535

HYDRAULIC SHOCK ABSORBER Filed "June 28, 1934 I ra BNVENTOR WALTER w.RIEDEL J BY M QL @55 ATTORNEYS 15 invention will be apparent from thefollowing stem of the pressure release valve 52 extends 1 Patented Oct.6, 1936 2,056,535

UNITED STATES PATENT OFFICE HYDRAULIC SHOCK ABSORBER Walter W. Riedel,Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., acorporation of Delaware Application June 28, 1934, Serial No. 732,744

Claims. (01. 2678) This invention relates to improvements in hyhas apassage 42 providing for the transfer of draulic shock absorbers. thefluid from one side of the piston to the other It is among the objectsof the present invenin response to its backward and forward movetion toprovide a hydraulic shock absorber with ment. The inner surface of thepiston head has 5 an automatic control device which will adjust the anannular ridge 43 about the inner end of pas- 5 shock absorber to varyits resistance to movesage 42, this ridge providing a seat against whichments of the body and axle of the vehicle in acintake valve 44 isyieldably urged by a spring 45 cordance with the nature of the roadbedover which is supported in a cage 45. This cage is which the vehicle isbeing operated. maintained in engagement with the inner sur- 1() Afurther object of the present invention is to face of the piston head bya spring 41 interposed iu provide a shock absorber having an automaticbetween the piston and the inner end of the cylcontrol device responsiveto accelerations in the inder 25, said spring 41! also maintaining thevertical movements of the vehicle body. head of the piston 45 inconstant engagement Further objects and advantages of the present withthe free end of the operating lever 35. The

description reference being had to the accomthrough an Opening 50 P d inthe intak panying drawing wherein a preferred embodivalve 44. A spring53, interposed between the ment of the present invention is clearlyshown. Valve 44 and an abutment pin 54 carried b In the drawing: valvestem 5|, normally urges the pressure-re- Figure 1 is a fragmentary sideview of the velease valve 52 into engagement with the valve hiclechassis, a shock absorber equipped with the 44 so that normallycommunication via opening 20 present invention being shown appliedthereto; 53 is cut off between the chamber 4| and the Figure 2 is alongitudinal sectional View taken Passage 42 in the head of the piston45. through the shock absorber, certain portions The structure so fardescribed operates as folthereof being shown in elevation for the sakeof lows: when the roadwheel of a vehicle strikes an 25 clearne s; nd,obstruction in the roadbed the axle is thrust Figure 3 is an enlargeddetail sectional view pwardly towa the sp 25 compressing the takensubstantially along the line 3-3 of Fig- Spring 22. The link 32 and theshock absorber ure 2, operating lever 3! are thrust upwardly and con-Referring to the drawing, the numeral 20 sequently the rocker shaft 35is rotated clockdo designates the frame of the vehicle which is sup-Wise as rega ds Figures 1 a t moving the ported upon the axle 2| bysprings 22, only one free end of the lever away from the cylinder ofwhich is shown. For the sake of clearness the 5. The spring 41 Wnaturally ur the piston roadwheels of the vehicle have been omitted from45 to follow the movement of lever 35 and consethi view, quently fluidwithin the reservoir 25 acting 35 The shock absorber comprises a casing23 prothrough piston head passage 42 will move the Viding a fluidreservoir 24 and a cylinder 25. A v lv 44 from engagement wi h t 43against channel 26 provides communication between the the effect ofspring 45. Now a substantially free fluid reservoir 24 and the interiorof the cylinflow of fluid is established from the reservoir 25 der 25.into the chamber 4|. 40

A rocker shaft 30 is transversely supported by When the sp i 22 m voward its normal the casing, one end of said rocker shaft extendloadposition, r, when the frame 20 of the veing outside of the casing andhaving the shock hicle moves upw y away from the axle 2! a absorberoperating arm 3| attached thereto, reverse movement of the shockabsorber obtains The free end of this arm is swivelly secured to andconsequently lever 35 will push the piston 45 45 one end of a link 32the other end of said link into the cylinder 25 against the effect ofspring 41. being swivelly secured to a member 33 anchored Now pressurewill be exerted upon the fluid within to the axle 2!. Within the shockabsorber casthe displacement chamber 4! which pressure ing the rockershaft 30 has an operating lever 35 when reaching a predetermined degreewill be exsecured thereto so as to rotate therewith the free ertedagainst the valve 52 to move it from en- 50 end of this lever lyingadjacent the open end of gagement with valve 44 against the effect ofthe cylinder 25. spring 53 thereby to establish a restricted flow ofWithin the cylinder 25 a piston 40 is provided, fluid from chamber llthrough the opening 50 said piston forming a fluid displacement chamberin valve 44 and passage 42 in piston 40 into the 55 4| within thecylinder 25. The head of the piston reservoir 24. The restriction tothis fluid flow 55 will resist shock absorber movement consequently theexpanding movement of the spring 22 is resisted as well as the movementof the frame 20 away from axle 2|.

One object of the present invention is to control the fluid flow fromchamber 4| through the passage 26 and out of port to in response to andproportionately with accelerations in the movements of the shockabsorber. This movement of the shock absorber is particularly the upwardmovement which may be termed the rebound. movement of the vehicle frame20.

This control device comprises an inertia weight- Gl hingedly supportedat one edge by a pin 62 rigidly carried by 21 depending tongue 63provided on the cover 64. This cover 64 is secured to the shock absorbercasing by screws 55. A properly gasketed plate 66 is clamped between thecover 64- and the shock absorber casing. This plate has a dependingtongue 61' which provides one abutment member for the spring 68, theother end of the spring being attached to an abutment post 69- securedto the weight by screw 70. An angular portion of the abutment 69 engagesthe member it which is adjustably carried by the cover 64 which, whenoperated in one direction, urges the weight M away from the cover and inthe other direction permits the spring 68 to move the weight 6| incloser proximity to said cover. Thus member H is adapted to be actuatedto vary the normal position in which the weight is held suspended byspring 68.

The port 68 through which passage 26 dis charges into reservoir 24 hasan annular, sharpedge valve seat 80 which is adapted to be engaged by avalve 8| s1idably carried within a cylindrical extension 82 of thecasing surrounding the port. Transverse openings 83 in the cylindricalextension 82 provide for the transfer of fluid from the port to thereservoir when the valve 8| is oif the seat 8|). The outer end of thevalve 8| is recessed as at 8 5 to receive the rounded end of anextension 85 provided at one end of a link 86 which forms one member of.a toggle joint. The end of this link opposite the extension 85- ishingedly attached to the other link 87 of the toggle joint by a pin 88.One end of the link 81 is pivoted to a fixed pin 89 carried by a lugformed in the wall of cylinder 25. A member 90 is secured to the weight6!, preferably molded therein, said member having an elongated slot 9|which fits over the pin 88 and operatively connects the weight with thehinge connection between the two links 86 and 8l of the toggle joint.This connection is such that when the weight BI is in normal suspendedposition the toggle joint will be maintained in the position as shown inFigure 2, in which the pin 89 of toggle link 81 and the end ofprojection 85 of toggle 86 are closest together. Under thesecircumstances any fluid pressure exerted against valve 8| will move itfrom its seat 86 and maintain said valve against the rounded end of linkextension 85. In this position port (58 is held open to permit apredetermined flow of fluid from said port through the transversepassages 83 into the reservoir 24.

This control device functions in the following manner: As has been saidbefore when the frame 28' moves away from the axle 2| the shock absorberoperates to move the piston 40 into the cylinder to exert pressure uponthe fluid therein. Normally valve 8| may be moved the normal distanceaway fro-m its seat 80 by the slightest pressure being exerted upon itand consequently under these conditions a flow of fluid will bepermitted from chamber 4|, passage 26, out of port 60 past the valve 8|through the openings 83 into the reservoir 24. Excessive pressure isrelieved by the movement of the valve 52 from engagement with valve 44to establish a flow through the piston head, as has been described. Now,if the upward movement of the frame 20 is accelerated to a predetermineddegree, a relative movement between the weight 6| and the shock absorbercasing obtains. Under these conditions the weight 6| will be moved aboutits pivot pin 62 in a clockwise direction as regards Figure 2 againstthe effect of spring 68. This movement of the weight 6| causes themember 90 to exert a pushing effort upon the pivot pin 88 of the togglelinks 81 and 86, movingsaid links toward their aligned position so thattheir outer ends will be moved a greater distance apart, which movementresults in the valve 8| being actuated toward its seat 80 and therebyincreasing its restriction to the fluid flow from the port 66. It mayclearly be seen that the valve 8| will be pushed toward the seat 80proportionately to the acceleration of the movement of the frame 20upwardly and consequently the restriction to the fluid flow from port 60is proportionate to the acceleration of the frame movement. The positionof the member 90' of the weight 6|= relative to its pivotal point 62together with the toggle joint provides for multiplication of the forceexerted by the weight. That is, the leverage between the weight 6| andthe valve 8| is of: such a character that the actuating force of theweight 6| to move valve 8| is substantially increased. From this it maybe seen that a comparatively small weight may be used toprovidesufficient pushing effort to overcome comparatively high fluidpressure from port 60.

The element H may be connected to any suitable adjusting mechanismavailable at the seatof the driver in the vehicle whereby the shockabsorber may be adjusted during the operation of the vehicle to vary itscontrol of its body movements.

From the aforegoing it may be seen that ap-g plicant has provided ashock absorber with an automatic control capable of adjusting the shockabsorber to vary its resistance to body and axle movement in accordancewith the nature of the roadbed over which the vehicle is being operated.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is-as follows:

1. A hydraulic shock-absorber having a fluid displacement chamberprovided with anoutlet port; a fluid displacement member; a valve forsaid port; a yieldably suspended inertia weight.

in the shock absorber; a toggle joint connecting the weight and'valve,and normally permitting the valve to maintain the port open, but adaptedto multiply the force of the weight upon the valve to overcome theeffect of fluid pressure acting;

directly upon the valve and tending to urge it into its port openposition.

2. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a fluid displacement member; a valve forsaid port; an inertia weight; an adjustable stop;

a spring urging said weight against the adjustable stop; and mechanical,force multiplying means connecting the weight and valve, and adapted'toactuate the valve only in direct opposition to the fluid pressuretending to move the valve to open the port.

3. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a fluid displacement member; a valve forsaid port; an inertia weight; a spring urging the weight normally toengage a stationary part of the shock absorber; and mechanical, forcemultiplying means attached to the weight and adapted to be engaged bythe valve for limiting its movement to open the port, said means urgingthe valve toward the port against the effect of the fluid pressure, inresponse to accelerations in the movement of the shock absorberupwardly.

4. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a fluid displacement member, a valve forsaid port; an inertia weight; a spring normally holding the weightagainst an adjustable stop on the shock absorber; a toggle jointconnected to the weight and adapted to limit the movement of the valveto open the port, said weight acting through said toggle joint toactuate the valve against the fluid pressure tending to move the valveto open the port, for restricting the flow of fluid from said port inaccordance with upward accelerations in the movement of the shockabsorber.

5. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a fluid displacement member; a valve forsaid port; an inertia weight yieldably urged against an immovableportion of the shock absorber; a toggle joint, the outer end of one linkof which is pivoted to the shock absorber, the outer end of the otherlink of the toggle joint engaging the valve to limit its port openingmovement by fluid pressure; and a member attached to the weight andengaging the pivotal connection between the two toggle links.

6. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a fluid displacement member; a valve forsaid port; an inertia weight pivotally supported in the shock absorber;an adjustable stop; a spring normally holding the weight against thestop; a toggle joint comprising two links hinged together, the outer endof one being pivotally secured to the shock absorber, the outer end ofthe other engaging the valve to limit its movement to open the port inresponse to fluid pressure; and a member connecting the weight with thehinged joint of the toggle whereby the weight, acting through thetoggle, actuates the valve against fluid pressure to restrict the flowof fluid from the port.

7. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a valve adapted to restrict the flow offluid through said port; an inertia weight held suspended against anadjustable member on the shock absorber by a spring, said weight beingmovable away from said member in response to accelerations in the upwardmovement of the shock absorber; and means operatively connecting theweight and valve, said means normally limiting the movement of the valveto open the port and being adapted to multiply the force of said weightagainst the valve having fluid pressure acting directly against ittending to move it to full port opening position.

8. A hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port; a toggle joint comprising two links hingedtogether, the outer end of one link being pivotally secured to the shockabsorber; an inertia Weight; an adjustable stop; a spring normallyholding the weight against the stop; means securing the Weight to thehinged connection of the links; and a valve for the port, urged by fluidpressure against the outer end of the other link which limits the fullport open position of the valve and which is adapted to actuate thevalve against the fluid pressure to restrict the fluid flow from saidport, in response to movement of the Weight by accelerations in theupward movement of the shock absorber.

9. In a hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port, the combination with an inertia mass; aforce multiplying means connected with said mass; and a valve for saidport, movable freely from port closing position into engagement withsaid means and adapted to be adjusted by the inertia mass acting throughsaid means to increase its restriction to fluid flow from said port.

10. In a hydraulic shock absorber having a fluid displacement chamberprovided with an outlet port, the combination with an inertia mass; atoggle connected to said mass and adapted to be actuated thereby; and avalve for the port, movable freely from said port into engagement withthe toggle and adapted to be adjusted by the weight acting through saidtoggle, to increase its restriction to fluid flow from said port.

WALTER W. RIEDEL.

